The present invention relates to the field of radiotelephone communications and more particularly to methods of transmitting and receiving incoming call pages in radiotelephone communications systems.
In a conventional mobile radiotelephone communications system, communications are provided between one or more mobile user terminals, a wired communications system, and the radiotelephone communications system. In other words, a radio link between a mobile user terminal and the radiotelephone communications system can be used to support communications between the mobile user terminal and a second mobile user terminal, or between the mobile user terminal and a telephone on the wired communications system.
When a call is placed to the mobile user terminal, the radiotelephone communications system sends an incoming call page to the mobile user terminal over a control channel indicating the presence of an incoming call. Upon reception of this incoming call page by the mobile user terminal over the control channel, the user terminal and the radiotelephone communications system initiate a series of control communications to establish a link therebetween over a dedicated channel.
In particular, the Asia Cellular Satellite (AceS) proposed by Lockheed Martin Corporation and Ericsson Mobile Communications AB provides that a sequence of up to 5 incoming call pages be transmitted by the satellite system in indication of an incoming call. Moreover, a predetermined uniform delay is provided between each of the incoming call pages of the sequence and a period of time (longer than the predetermined uniform delay) is provided after the last page of the sequence within which the user can respond to the incoming call to establish a radiotelephone communications link.
Because the mobile user terminal may be unable to receive or respond to the initial incoming call page, however, a sequence of multiple incoming call pages may be sent. Furthermore, one or more of the sequence of incoming call pages may be sent at an increased power level (such as over a High Power Alert Channel) to increase the probability of being received by the mobile user terminal. Accordingly, the mobile user terminal can respond to the incoming call any time between the first and last pages of the sequence of pages as well as within the predetermined period of time provided after the last page of the sequence.
In particular, a mobile user terminal may be operating under disadvantaged communications conditions so that one or more of a sequence of incoming call pages are received, but the mobile user terminal is unable to immediately respond. For example, a mobile user terminal in a location, such as inside a building, providing disadvantaged communications may be able to receive one of the sequence of incoming call pages, such as a page in the sequence sent over a high power alert channel, but be unable to respond until taken to a location, such as outside the building, providing advantaged communications.
The time to respond to the page may expire while the user is attempting to get outside causing user frustration. Furthermore, it may be difficult to distinguish between different sequences of pages associated with closely spaced incoming calls if the user terminal does not receive all pages of each sequence.
It is therefore an object of the present invention to provide improved methods of transmitting and receiving incoming call pages and related user terminals and communications systems.
This and other objects are provided according to the present invention by including information in the incoming call pages which allows the receiving user terminal to determine a period of time available for response if communications cannot be established immediately. An indication of this period of time can then be provided to the user who is able to decide if there is sufficient time to try to move to a location which will allow communications to be established. For example, the mobile user terminal may be in a building when a high power incoming call page is received and may be unable to respond immediately because of interference due to the building. By moving outside within the period of time allowed for response, however, the mobile user terminal can respond to the incoming call. The frustration of moving outside the building to only then learn that the time for response has elapsed can thus be reduced. Moreover, one or more of the pages in a sequence can be missed without shortening the period allowed for response.
According to a first aspect of the present invention, the incoming call page from the radiotelephone communications system is received at the mobile user terminal. The period of time within which the mobile user terminal can respond to the incoming call is then determined, and an indication of this period of time is provided to the user. In addition, the incoming call page can be one of a predetermined number of incoming call pages addressed to the mobile user terminal in a sequence wherein each of the incoming call pages in the sequence includes information identifying the respective incoming call page within the sequence. Accordingly, the step of determining a period of time within which the mobile user terminal can respond to the incoming call can include determining the number of incoming call pages in the sequence to follow.
More particularly, the information identifying the respective incoming call page within the sequence can include a number that is incremented or decremented for each successive incoming call page in the sequence. In addition, the mobile user terminal can receive timing information including a time duration between each of the incoming call pages in a sequence and including a predetermined period of time after a last of the incoming call pages in a sequence within which the mobile user terminal can respond to the incoming call. Moreover, the timing information can be received as a portion of each of the incoming call pages, the timing information can be received over a control channel independent of the incoming call pages, and/or the timing information cab be programmed into mobile user terminal memory. Preferably, the timing information is received over a control channel independent of the incoming call pages.
According to an alternate aspect of the present invention, a radiotelephone communications system determines that there is an incoming call for the mobile user terminal, and transmits a predetermined number of incoming call pages addressed to the mobile user terminal in a sequence. Each of the incoming call pages in the sequence includes information allowing the user terminal to determine a period of time within which the mobile user terminal can respond to the incoming call. Accordingly, the mobile user terminal can determine the period of time available for response to the incoming call and provide this information to the user.
Methods, terminals, and systems according to the present invention thus allow the recipient of an incoming call to make an informed decision as to whether there is enough time to move from a location providing disadvantaged communications to a location providing advantaged communications in response to an incoming call. User frustration can thus be reduced.